1. Field of Invention
This invention relates to a hemostatic material, and particularly to a hemostatic material that contains a nano-fiber containing a synthetic collagen.
2. Description of Related Art
A fiber having a nanometer-scale diameter (1 nm to 1000 nm) exhibits different material properties as compared to fibers having micrometer-scale or larger diameters, and is generally called a nano-fiber to distinguish from other fibers. For a nano-fiber has a very large surface area per unit weight, that is, a very large specific surface area, its applications in carrier materials of functional molecules, fluid-contact reaction materials, cloth materials, industrial material products, living material products, environmental material products, electrodes and membranes of fuel cells and rechargeable batteries, regenerative medicine materials, ultrahigh-performance filters, electronic papers, wearable cells, protective clothing and so on have been investigated, and the studies and developments thereof in the respective fields have been extensively conducted. Moreover, the affects of nano-fiber materials to cells, etc. have received a lot of attention, and there are numerous reports on the studies of medical materials utilizing nano-fibers.
Currently, collagen, being a type of protein, is widely used as a general medical material. The natural type-one collagen molecule has a characteristic primary structure formed by a repetition of three amino-acid residues, Gly-X-Y, wherein X and Y are selected from various amino acids; but in most cases, X is Pro and Y is Hyp. Three chains of the polypeptide having the same orientation together constitute a triple-helix tertiary structure and form a collagen fiber.
On the other hand, a synthetic collagen molecule, which was created as a collagen-like peptide and is formed by a repetition of three amino-acid residues, Pro-Y-Gly (Y is proline or hydroxyproline), has also been reported to have a triple helix structure, and has been studied as various functional materials, as described in Patent Document 1.
Particularly, Patent Document 2 has reported a sponge-like hemostatic material, which is obtained by freeze-drying a hemostatic material that contains thrombin and a synthetic collagen containing a peptide unit represented by Pro-Y-Gly.
However, the hemostatic material disclosed in Patent Document 2 contains, as an essential component, thrombin that is a blood coagulation factor, and the hemostatic function of the synthetic collagen itself is unknown. Moreover, the operatability and the productivity of the hemostatic material are also desired to be improved.
The nano-fiber formed from the synthetic collagen can be made into a highly functional material or a multi-functional material by controlling the sequence of the amino acid residues and also utilizing the chemical modifiability and so on of the amino acid residues. Moreover, when such nano-fiber is used as the raw material of a hemostatic material, the operatability is improved.
However, different from the case of the natural collagen, such synthetic collagen has a poor interaction between its high-molecular peptide chains because of the simple repetition structure formed from Pro-Y-Gly only, and exhibits a high solubility in water. Hence, a long fiber like the natural collagen fiber still cannot be formed currently.